The driving and control device according to the present invention provides
a desired switched current to a load including a string of one or more
electronic devices, and comprises one or more voltage conversion means,
one or more dimming control means, one or more feedback means and one or
more sensing means. The voltage conversion means may be a DC-to-DC
converter for example and based on an input control signal converts the
magnitude of the voltage from the power supply to another magnitude that
is desired at the high side of the load. The dimming control means may
comprise a switch such as a FET, BJT, relay, or any other type of
switching device, for example, and provides control for activation and
deactivation of the load. The feedback means is coupled to the voltage
conversion means and a current sensing means and provides a feedback
signal to the voltage conversion means that is indicative of the voltage
drop across the current sensing means which thus represents the current
flowing through the load. The current sensing means may comprise a fixed
resistor, variable resistor, inductor, or some other element which has a
predictable voltage-current relationship and thus will provide a
measurement of the current flowing through the load based on a collected
voltage signal. Based on the feedback signal received, the voltage
conversion means can subsequently adjust its output voltage such that a
constant switched current is provided to the load.